FIG. 5 shows a prior art buried type semiconductor laser as a semiconductor light emitting device.
As illustrated in FIG. 5, a prior art buried type semiconductor laser starts with an n-type InP substrate 1. A p-type InP blocking layer 2, an n-type InP blocking layer 3, and an InGaAsP active layer 70 are successively grown on the n-type InP substrate 1 by such as liquid phase epitaxy. A V-shaped groove 60 is produced through three layers 70, 3, and 2 so as to reach into the substrate 1 such as by etching. An n-type InP cladding layer 51 is buried in the V-shaped groove 60 and an InGaAsP active layer 71 is produced on the n-type InP cladding layer 51. A p-type InP cladding layer 80 is grown on the InGaAsP active layer 71 in the groove 60 and on the InGaAsP active layer 70 outside the groove 60 and the surface thereof is made flat. A p-type InGaAsP contact layer 90 is produced on the p-type InP cladding layer 80. A p side electrode 100 is provided on the p-type InGaAsP contact layer 90 and an n side electrode 110 is provided on the n-type InP substrate 1.
The device operates as follows.
When a voltage is applied between the p side electrode 100 and the n side electrode, a current flows only through the V-shaped groove 60 which is between the p-type InP blocking layer 2 and the n-type InP blocking layer 3. The current stimulates emission of laser light at the InGaAsP active layer 71 buried in the V-shaped groove 60.
In this prior art buried type layer of such a construction, the position control of the InGaAsP active layer 71 in the V-shaped groove 60 is difficult because of the shape of the groove. Further, due to pn junctions existing at the periphery of the V-shaped groove the parasitic capacitance is large resulting in leakage current and limitation of response speed. In addition, since the p side electrode 100 and the n side electrode 110 are produced at opposing surfaces of the n-type InP substrate 1, the device is difficult to integrate with other electronic elements.